REEF RELIEF: Coral reefs like this one may hold the secret to green sunscreen. (Photo: ZUMA Press)

Sunscreen may help prevent skin cancer, but it's still a bummer to put on. What if, instead of lathering yourself in greasy lotions, you could just take a sunscreen pill?

According to new research by scientists at King's College of London, that might soon be an option. They've discovered a natural compound in coral reefs that protects against the sun's harmful ultraviolet rays, and they're now "very close" to synthesizing it in a lab. Once they do that, it could lead to an oral sunscreen pill for human use — possibly within five years.

It may also offer other benefits, the researchers add, such as genetically modified crops that can thrive in the tropics despite exposure to harsh UV rays.

So why do corals, of all animals, make sunscreen? It's an adaptation to their strange lifestyle: Corals are symbiotic, absorbing photosynthetic algae into their bodies so they can be fed from within. The algae, in turn, are safe from predators and use the corals' waste for photosynthesis. This partnership has created huge coral reefs around the world, but it also has a major flaw: Since the reefs need sunlight to make food, most live in shallow water near the ocean's surface. And that exposes them to UV rays.

UV rays are especially intense in the tropics, where many coral reefs are known to protect themselves by making their own sunscreen. But until now, scientists never knew how they did it — or how we could mimic them. According to researcher Paul Long, who led the King's College study, the key is cooperation.

"What we have found is that the algae living within the coral makes a compound that we think is transported to the coral, which then modifies it into a sunscreen for the benefit of both the coral and the algae," Long says in a statement. "Not only does this protect them both from UV damage, but we have seen that fish that feed on the coral also benefit from this sunscreen protection, so it is clearly passed up the food chain. This led us to believe that if we can determine how this compound is created and passed on, we could biosynthetically develop it in the laboratory to create a sunscreen for human use, perhaps in the form of a tablet, which would work in a similar way."

The idea of sunscreen pills isn't new — they're already sold over the counter, under brand names like Heliocare, Fernblock and Sunpill. Many are even based on natural compounds, such as the antioxidants Polypodium leucotomos or astaxanthin. But while some studies have found them to be at least mildly effective, a few of those studies have also been criticized for small sample sizes and other poor research methods. Sold as dietary supplements, the current pills aren't regulated by the FDA, and their labels warn they should only be used with sunscreen, not instead of it.

Corals can't buy Coppertone, though, so they must rely entirely on their DIY sunscreen. And now researchers at King's College are hoping humans can, too — and soon. Long says that "if all goes well, we would expect to test it within the next two years." And speaking to the Guardian, he even offers an estimate on when it might hit the market. "There would have to be a lot of toxicology tests done first," he says, "but I imagine a sunscreen tablet might be developed in five years or so."

Such a tablet may have to be prescription-only, the Guardian points out, to limit the chances of people overdosing. Skin needs some sunlight, and too much protection could lead to vitamin D deficiency and weak bones. Still, Long argues the potential benefits outweigh the risks. "Nothing like it exists at the moment," he says.

On top of sunscreen pills, Long hopes the coral compound can also boost sustainable agriculture in the tropics. "If we do this in crop plants that have been bred in temperate climates for high yield, but that at present would not grow in the tropics because of high exposure to sunlight, this could be a way of providing a sustainable nutrient-rich food source, particularly in need for Third World economies," he says.

And while this research hints at huge benefits for humans, it may also be good for coral reefs themselves. While studying in Australia's Great Barrier Reef, Long and his colleagues have been studying the process of coral bleaching, considered a growing threat due to rising ocean temperatures from global warming. By examining corals' genetic and biochemical changes as they're exposed to sunlight in warmer water, the researchers hope to better understand how bleaching works and how to fight it.

Source: Mother Nature Network